About 75% of the R51 owners who frequent this forum probably have them, including me! They work great on the R51's. I would imagine they'd be just as good on the R50.
It's not an issue on the R51, which has a completely different rear suspension that the R50. I'm not sure if it's an issue on the R50, but if you go to Airlift's website, they will likely have downloadable instructions that would tell you. Instructions also come in the kit, of course.
Installed, ran me 120 to replace rear springs and put in airlift....and yeah WOW!!!!!!!
Such a difference, wish i knew about these years ago. Feels like a brand new SUV. Running 16.5PSI with all 3 kids in back feels perfect!